Adaptive incremental blood pressure monitor
First Claim
1. A method for automatically measuring blood pressure in a living animal test subject, comprising the steps of:
- (a) applying a predetermined initial pressure externally to the body of the test subject adjacent a blood vessel;
(b) recording the value of the applied pressure and the amplitude of pressure pulses withing the blood vessel due to the operation of the heart of the test subject;
(c) incrementally increasing the applied pressure at least once and repeating the recording step (b) after each increment;
(d) if the amplitudes of the pulses increase with incremental increases of the applied pressure above the predetermined pressure and then decrease, (i) designating the applied pressure when the pulse amplitude is greatest as mean arterial pressure, (ii) designating as systolic pressure the applied pressure above mean arterial pressure where the pulse amplitude is a first fixed fraction of the amplitude at mean arterial pressure, and (iii) designating as diastolic pressure the applied pressure below mean arterial pressure at which the pulse amplitude is a second fixed fraction of the amplitude at mean arterial pressure;
(e) if the amplitudes of the pulses first decrease with incremental increases of the applied pressure above the predetermined initial pressure, changing said applied pressure to a new applied pressure that is a certain amount below the predetermined initial pressure, and repeating steps (b)-(d) until mean arterial pressure and systolic pressure are determined;
(f) halting the incremental changes in applied pressure after the determination of systolic, diastolic and mean arterial pressure; and
(g) relieving the applied pressure.
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Accused Products
Abstract
An adaptive monitor and method for rapidly determining blood pressure, selects an initial cuff pressure to be applied to an artery of the test subject and then measures the amplitude of pressure pulses caused by the pumping of blood by the subject'"'"'s heart. The cuff pressure is incrementally increased while the pulse amplitudes are monitored in order to obtain blood pressure readings by the oscillometric method. If the pulse amplitudes decrease for increases in pressure above the initial value, it is taken as an indication that mean arterial pressure is below the initial cuff pressure. Thus the cuff pressure is substantially decreased to a new initial value and the process is restarted. If it should be found upon a determination of the mean arterial pressure and the systolic pressure, that the initial or new cuff pressure was not low enough to determined diastolic pressure, the cuff pressure is automatically decreased in one large step to a level below the initial pressure and is then decreased in steps until diastolic pressure is located.
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Citations
11 Claims
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1. A method for automatically measuring blood pressure in a living animal test subject, comprising the steps of:
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(a) applying a predetermined initial pressure externally to the body of the test subject adjacent a blood vessel; (b) recording the value of the applied pressure and the amplitude of pressure pulses withing the blood vessel due to the operation of the heart of the test subject; (c) incrementally increasing the applied pressure at least once and repeating the recording step (b) after each increment; (d) if the amplitudes of the pulses increase with incremental increases of the applied pressure above the predetermined pressure and then decrease, (i) designating the applied pressure when the pulse amplitude is greatest as mean arterial pressure, (ii) designating as systolic pressure the applied pressure above mean arterial pressure where the pulse amplitude is a first fixed fraction of the amplitude at mean arterial pressure, and (iii) designating as diastolic pressure the applied pressure below mean arterial pressure at which the pulse amplitude is a second fixed fraction of the amplitude at mean arterial pressure; (e) if the amplitudes of the pulses first decrease with incremental increases of the applied pressure above the predetermined initial pressure, changing said applied pressure to a new applied pressure that is a certain amount below the predetermined initial pressure, and repeating steps (b)-(d) until mean arterial pressure and systolic pressure are determined; (f) halting the incremental changes in applied pressure after the determination of systolic, diastolic and mean arterial pressure; and (g) relieving the applied pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. Apparatus for automatically measuring blood pressure in a living animal test subject comprising:
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means for automatically applying a variable pressure externally to the body of the test subject adjacent a blood vessel; means for detecting the value of the applied pressure as well as the amplitude of pressure pulses within the blood vessel due to the operation of the heart of the test subject; means for storing in a correlated fashion the values of applied pressure and the amplitude of pressure pulses detected at those applied pressures; means for incrementally increasing the applied pressure in pressure increments from a predetermined pressure; means for determining the applied pressure at which the pulse amplitude is maximum and indicating that pressure as mean arterial pressure, and the applied pressures above and below mean arterial pressure at which the pulse amplitudes are certain fixed ratios of the pulse amplitude at mean arterial pressure and indicating them as systolic and diastolic pressure, respectively; means for detecting an increase or decrease in the pulse amplitudes prior to reaching the maximum pulse amplitude; and means for causing a fixed drop in the applied pressure, which is substantially larger than the incremental increases, when said means for detecting an increase or decrease detects a decrease in pulse amplitudes for increases in applied pressure immediately above the predetermined pressure. - View Dependent Claims (10, 11)
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Specification